The purpose of this clinical study is to confirm safety and efficacy in the clinical magnetic resonance imaging (MRI) environment of the investigational EnRhythm MRI™ SureScan™ Pacing System (used in support of Revo MRI™ SureScan Pacing System launch).

Subjects with a complication related to the MRI scan. All adverse events in the time frame were recorded at the subject's center and assessed by a centralized Adverse Event Advisory Committee. The committee determined whether each adverse event was a complication (requiring invasive intervention), and whether the event was related to the MRI scan.

Subjects' atrial pacing capture threshold (the energy sent from the pacemaker needed to make the heart's atrium beat) was measured at the 9-12 week visit (before the MRI scan was performed for those in the MRI group) and at the 4-month visit (one month post-MRI). Subjects were considered successful if their pacing capture threshold did not increase by 1.0 volt (V) or more.

Subjects' ventricular pacing capture threshold (the energy sent from the pacemaker needed to make the heart's ventricle beat) was measured at the 9-12 week visit (before the MRI scan was performed for those in the MRI group) and at the 4-month visit (one month post-MRI). Subjects were considered successful if their pacing capture threshold did not increase by 1.0 volt (V) or more.

Subjects' atrial sensed amplitude (the minimum energy produced by the heart's atrium that the pacemaker can sense) was measured at the 9-12 week visit (before the MRI scan was performed for those in the MRI group) and at the 4-month visit (one month post-MRI). Subjects were considered successful if their sensed amplitude did not decrease by more than 50% and remained above 1.5 millivolts (mV).

Subjects' ventricular sensed amplitude (the minimum energy produced by the heart's ventricle that the pacemaker can sense) was measured at the 9-12 week visit (before the MRI scan was performed for those in the MRI group) and at the 4-month visit (one month post-MRI). Subjects were considered successful if their sensed amplitude did not decrease by more than 50% and remained above 5.0 millivolts (mV).

Subjects with a complication related to the implanted system, which consisted of the pacemaker, leads to the right chambers of the heart (atrium and ventricle), pacemaker software, and programmer. All adverse events in the time frame were recorded at the subject's center and assessed by a centralized Adverse Event Advisory Committee. The committee determined whether each adverse event was a complication (requiring invasive intervention), and whether the event was related to the system.

Number of participants with adverse device effects (ADEs) that resulted from insufficiencies or inadequacies in the instructions for use or deployment of the device, or from user error. ADE's were investigator-reported.

Occurrence of Arrhythmias [ Time Frame: During the MRI scan ] [ Designated as safety issue: No ]

Number of participants with sustained ventricular arrhythmias or asystole episodes that occurred during the MRI scan that were considered attributable to the MRI scan

Subjects' atrial lead impedance (a measure of electrical resistance) was measured at the 9-12 week visit (before the MRI scan was performed for those in the MRI group) and at the 4-month visit (one month post-MRI). Both measurements were conducted by the pacemaker. The difference between the two is reported.

Subjects' ventricular lead impedance (a measure of electrical resistance) was measured at the 9-12 week visit (before the MRI scan was performed for those in the MRI group) and at the 4-month visit (one month post-MRI). Both measurements were conducted by the pacemaker. The difference between the two is reported.

The MRI group underwent a one-hour MRI scan at the 9-12 weeks post-implant follow-up.

Device: Implantable Pulse Generator (IPG) and Pacing Leads (wires)

Pacer and leads

Other: Magnetic Resonance Imaging (MRI) scan

One hour MRI scan on the head and lower back.

Control group

The control group waited for one hour (no MRI) at the 9-12 weeks post-implant follow-up.

Device: Implantable Pulse Generator (IPG) and Pacing Leads (wires)

Pacer and leads

Detailed Description:

This study is a prospective, multi-center global study.

Eligibility

Ages Eligible for Study:

Child, Adult, Senior

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria:

Subject has, or is at risk of having, a heart beat that is too slow and his/her doctor has determined he/she needs a pacemaker.

Subject available for follow-up at study center for length of study.

Subject able and willing to undergo elective MRI scanning without sedation.

Exclusion Criteria:

Subject has, or is at risk of having, a heart beat that is too fast and his/her doctor has determined he/she needs an implantable cardioverter defibrillator (ICD).

Subject needs or will need another MRI-scan, other than those required by the study, during the required study follow-up period.

Pregnant women, or women of child bearing potential who are not on a reliable form of birth control.

Subject with exclusion criteria required by local law.

Subject who intends to participate in another clinical study during this clinical study.

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00433654